The woman in charge of AMG communications said rather curtly that the 12-cylinder S65 test-cars have all been assigned to writers from "our most important markets".
And this was after a senior executive personally extended an invitation to Life! to try the V12.
"You'd have to wake up early though," I remember him saying. "There are very limited number of cars."
So, there I was at the front desk, before the birds were in full song, hoping to secure the key to one of Mercedes' hallowed rocket limos.
But Ms Uptight said nein. Take the eight-cylinder S63 instead. Not wanting to go into a discourse on Mercedes' sales ranking in Singapore and the Republic's inordinately high per capita ownership of luxury cars in my pyjamas, I nodded.
As it turns out, the S63 AMG is amply suited to popping bleary eyes. Not with a jolt like a bottle of Red Bull, but like a freshly brewed cuppa. You feel the warm caffeine coursing through your veins, from your belly to your chest, your neck and then bingo - you are wide awake.
The car is furnished even more elaborately than a non-AMG S-class. The leather-lined cockpit, cushy seats and sound room-like insulation would have lulled anyone into a slumber.
But the 5.5-litre twin-turbo V8 simmering beyond the dashboard counters the snooze-inducing cabin by offering a performance worth writing home about.
With a tremor-inducing torque of 900Nm from just 2,250rpm, the forced induction V8 turns the Mercedes flagship sedan into a limo with an attitude.
More lethal than the Audi S8, the German juggernaut flies to 100kmh in four seconds flat, courtesy of an all- wheel-drive system that minimises wheelspin during ballistic take-offs.
While the sprint timing is not quite in the league of supercars, it is astounding for something that is over 5m long and weighs about two tonnes.
Top speed is limited to a relatively tame 250kmh, but the S63 AMG feels like it can manage 300kmh without panting hard.
Yet, at the wheel, the rarefied Merc comes across more like a cruise liner than a cruise missile.
Power delivery is satiny, with plenty of reserves across its relaxed rev range. Its ride is incredibly pliant, not unlike what a normal S-class offers. The difference is detectable only with generous shoves of either pedal. The car betrays less dive and squat than a garden variety S-class.
Hard acceleration brings forth a restrained guttural growl from the engine. This is less booming than what you expect of an AMG, but preserves the dignity and standing of the luxury model.
The drive of less than 100km, offered on the sidelines of the Mercedes AMG-GT S test drive, is but a taste of what the S63 is capable of. Still, it is enough to convey the specialness of the steroidal S-class.
The car is not available in showrooms in Singapore, but well-heeled Mercedes AMG fans can place special orders with Cycle & Carriage if they desire the rare and revvy land yacht. Those who want the V12 version might have to get past Ms Uptight first, though.